Customized video processing modes for HD-capable set-top decoders

ABSTRACT

A method ( 100; 200 ) and apparatus ( 230 ) for controlling a display of video being output from a set-top box determines ( 102 ) if a user selected channel contains programming having a first aspect ratio and stretches ( 106 ) automatically video from the user selected channel having the first aspect ratio, if the user selected channel contains programming having the first aspect ratio, to fill a frame having a second aspect ratio that is different than the first aspect ratio using a predetermined stretching function. This determining and stretching is initiated automatically upon tuning ( 101 ) to a user-selected channel. According to another aspect of the present invention, an exemplary embodiment ( 200 ) of a method for controlling video output from a set-top box, upon receiving a zoom toggle command from a user via a remote control unit, the method determines ( 202 ) if a user-selected program includes a second aspect ratio different than a first aspect ratio and ignores ( 205 ) the zoom toggle command if the programming does not include the second aspect ratio. If the programming does include the second aspect ratio, then the method selects ( 206; 208 ) a next available zoom mode for a first or second aspect ratio television type if the television type setting is set for the first or second aspect ratio, respectively, and sets ( 207; 210 ) an output format to a mode specified by a first predetermined output setting.

FIELD OF THE INVENTION

The present invention is directed generally to methods and apparatusesfor processing video signals at user premises, and more particularly toa method and apparatus for processing a video signal at a user premises,in which the video signal originates at a broadcast location.

BACKGROUND

The transition from NTSC standard definition to ASTC high definitionbroadcasting means that consumers are no longer watching only 4:3 aspectration programs. With the transition to widescreen high definitionbroadcasts, programs can be broadcast in 4:3 or 16:9 aspect ratios. Ofthose broadcast in 16:9 high definition formats, the actual video maynot fill the entire 16:9 screen. There will be black bars to the leftand right of the image. These black bars can cause fading issues withtelevisions and can be annoying to viewers.

The present invention is therefore directed to the problem of developinga method and apparatus for controlling presentation of video images tolimit the use of black bars on television screens when an image is beingdisplayed on a screen for which the image is not optimal.

SUMMARY OF THE INVENTION

The present invention solves these and other problems by providing interalia a method and apparatus for controlling a display of video beingoutput from a set-top box.

According to one aspect of the present invention, an exemplaryembodiment of a method for controlling an image being output from aset-top box determines if a user selected channel contains programminghaving a first aspect ratio and stretches automatically video from theuser selected channel having the first aspect ratio, if the userselected channel contains programming having the first aspect ratio, tofill a frame having a second aspect ratio that is different than thefirst aspect ratio using a predetermined stretching function. Thisdetermining and stretching is initiated automatically upon tuning to auser-selected channel.

According to another aspect of the present invention, an exemplaryembodiment of a method for controlling video output from a set-top box,upon receiving a zoom toggle command from a user via a remote controlunit, the method determines if a user-selected program includes a secondaspect ratio different than a first aspect ratio and ignores the zoomtoggle command if the programming does not include the second aspectratio. If the programming does include the second aspect ratio, then themethod selects a next available zoom mode for a first or second aspectratio television type if the television type setting is set for thefirst or second aspect ratio, respectively, and sets an output format toa mode specified by a first predetermined output setting.

According to still another aspect of the present invention, an exemplaryembodiment of an apparatus for controlling a video image output from aset-top box includes a processor and a memory. The memory is coupled tothe processor and stores encoded, computer readable instructions thatcause the processor to control an image being output to a display by:determining if a user selected channel contains programming having afirst aspect ratio; and stretching automatically video from the userselected channel having the first aspect ratio, if the user selectedchannel contains programming having the first aspect ratio, to fill aframe having a second aspect ratio that is different than the firstaspect ratio using a predetermined stretching function.

According to yet another aspect of the present invention, an exemplaryembodiment of an apparatus for controlling video includes a remotecontrol unit, a receiver, a processor and a graphical user interface.The receiver interacts with the remote control unit to receive a zoomtoggle command from a user via said remote control unit. The processordetermines if a user-selected program includes a second aspect ratiodifferent than a first aspect ratio and ignores the zoom toggle commandif the programming does not include the second aspect ratio. Thegraphical user interface enables a user can to enter a television typesetting via a user settings screen. The processor determines thetelevision type setting from the user settings screen and selects a nextavailable zoom mode for a first or second aspect ratio television typeif the television type setting is set for the first or second aspectratio, respectively, and sets an output format to a mode specified by afirst predetermined output setting.

Other aspects of the present invention will be apparent to thosereviewing the following drawings in light of the specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a screen image having a widescreen 16:9 aspect ratio.

FIG. 2 depicts the screen image of FIG. 1 in a standard 4:3 aspectratio.

FIG. 3 depicts the screen image of FIG. 1 in a hybrid 14:9 aspect ratio.

FIG. 4 depicts a letterbox display of a widescreen image on a standardscreen HDTV.

FIG. 5 depicts a full screen display of a widescreen image on a standardscreen HDTV.

FIG. 6 depicts pillarbox display of a standard screen image on awidescreen HDTV.

FIG. 7 depicts an example of screen fade on a widescreen HDTV.

FIG. 8 depicts a linear stretch display of a standard screen image on awidescreen HDTV.

FIG. 9 depicts a zoom display of a standard screen image on a widescreenHDTV.

FIG. 10 depicts DTV output formats and corresponding aspect ratios.

FIG. 11 the common 15:9, 14:9 and 4:3 hybrid aspect ratio broadcasts.

FIG. 12 depicts representative images used to illustrate the ASTB 16:9zoom Modes according to one aspect of the present invention.

FIGS. 13-15 depict the representative images from FIG. 12 for thevarious zoom Modes for 16:9 aspect ratios according to another aspect ofthe present invention.

FIGS. 16-18 depict the representative images from FIG. 12 for thevarious zoom Modes for 4:3 aspect ratios according to another aspect ofthe present invention.

FIG. 19 depicts an exemplary embodiment of a method for controlling adisplay of an image from video being output by a set top box accordingto still another aspect of the present invention.

FIG. 20 depicts an exemplary embodiment of a method for controlling adisplay of an image from video being output by a set top box accordingto yet another aspect of the present invention.

FIG. 21 depicts an exemplary embodiment of an apparatus for controllinga display of an image from video being output by a set top box accordingto still another aspect of the present invention.

FIG. 22 depicts an exemplary embodiment of a method for controlling adisplay of an image from video being output by a set top box accordingto yet another aspect of the present invention.

DETAILED DESCRIPTION

It is worthy to note that any reference herein to “one embodiment” or“an embodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the invention. The appearances of thephrase “in one embodiment” in various places in the specification arenot necessarily all referring to the same embodiment.

Introduction

The exemplary embodiments of the present invention relate to videoprocessing features for digital set-top boxes (e.g., the DCT-5100High-Definition digital cable set-top box) and television receivers.During the transition to all-digital television broadcasts, thereremains considerable confusion regarding the various resolutions, aspectratios, and scan formats inherent in the new ATSC Digital Television(DTV) standard. The consumer electronics industry remains withoutagreement on the optimal manner to process the large number of videobroadcast formats that are now in use. Presented with more viewingchoices than ever before, in terms of what programming is available forviewing and in what format programming may be viewed, consumers willremain faced with a significant learning curve to become comfortablewith digital television. In response to this confusion, the exemplaryembodiments herein include features for a digital set-top box thatprovide for greater viewing flexibility for a wide variety of consumerswho own a wide variety of HDTV sets.

The embodiments herein are also applicable to any set-top boxes orreceivers that include high definition decoding capabilities.

ATSC Video Formats

The ATSC has defined 18 Digital television (DTV) formats that includeHigh Definition, Enhanced Definition, and Standard Definitionresolutions. The formats represent a combination of picture resolutions,aspect ratios, and scan modes. The 18 ATSC DTV formats are presented inTable 1 with the most commonly-used formats shaded in gray. TABLE 1Vertical Horizontal Frame Rate Pixels Pixels Pixel Shape Aspect RatioScan Mode (frames/second) HD 1080 1920 Square 16:9 Progressive 24 10801920 Square 16:9 Progressive 30 1080 1920 Square 16:9 Interlaced 30 7201280 Square 16:9 Progressive 24 720 1280 Square 16:9 Progressive 30 7201280 Square 16:9 Progressive 60 ED 480 704 Rectangular 16:9 Progressive24 480 704 Rectangular 16:9 Progressive 30 480 704 Rectangular 16:9Progressive 60 480 704 Rectangular  4:3 Progressive 24 480 704Rectangular  4:3 Progressive 30 480 704 Rectangular  4:3 Progressive 60480 640 Square  4:3 Progressive 24 480 640 Square  4:3 Progressive 30480 640 Square  4:3 Progressive 60 SD 480 704 Rectangular 16:9Interlaced 30 480 704 Rectangular  4:3 Interlaced 30 480 640 Square  4:3Interlaced 30

Each format has a clearly defined vertical resolution, horizontalresolution, pixel shape, aspect ratio, scan mode and associated framerate.

Picture Resolution

The resolution of an ATSC DTV image is measured in horizontal andvertical pixels. A pixel is a tiny piece of the overall image. Thegreater the number of pixels, the more detail and sharpness an imagewill have. The original NTSC analog television format measuredresolution in terms of the number of vertical lines, but in an effort tobegin merging televisions and computer monitors under a single standard,the ATSC has opted to define video resolution in pixels. The HD videoformats have a vertical resolution or either 720 pixels or 1080 pixels.The ED and SD video formats have a vertical resolution of 480 pixels.

Pixel Shape

Early models of analog televisions used pixels that were rectangular inshape that were taller than they were wide. This was mostly due to theway that cathode ray tubes were able to draw images on the screen andnot necessarily an intentional characteristic. When computer monitorswere developed, cathode ray tube technology was further advanced andthey were able to generate pixels that were square in shape. In aneffort to bring designs for televisions and computer monitors closertogether, the ATSC has defined some DTV formats that specifically usesquare pixels (such as the HD video formats). DTV-capable televisionsmust be able to draw both square and rectangular pixels on theirscreens, which allows them to display both television and computer videoimages.

Aspect Ratio

Aspect ratio is the measure of an image's width to its height and isgenerally expressed as (w:h). The original NTSC analog televisionstandard specified a single aspect ratio that was 4:3. Since there wasonly one aspect ratio available, television manufacturers built theirsets to have display screens that matched the 4:3 images. As a result,the overwhelming majority of television sets and television programshave the 4:3 aspect ratio. As a result, the 4:3 aspect ratio is oftenreferred to as the “standard screen” or “full screen” format.

The ATSC DTV formats can have one of two possible aspect ratios—either4:3 or 16:9. Since the ATSC was primarily concerned with reinventing theway that people watch television, and to further increase the visualimprovements of the new HD formats, the ATSC opted to institute the 16:9(as referred to as “widescreen”) aspect ratio for the new HD formats.Images with 16:9 aspect ratios are typically more impressive andattractive to the human eye since the field of vision of a human eye ismuch more broad than it is high. Widescreen images tend to fill more ofour field of vision and create a more panoramic viewing experience,which is why most motion pictures are filmed in widescreen formats. Aside-by-side comparison of widescreen and standard screen aspect ratiosis presented below in FIG. 1 and FIG. 2.

To further complicate issues, broadcasters have adopted several “hybrid”aspect ratios to help bridge the gap and ease the transition from theNTSC 4:3 standard to the eventual ATSC 16:9 standard. These hybridaspect ratio programs are actually broadcast in a 16:9 format, however,the video within the 16:9 frame does not fill the entire frame. One verypopular hybrid aspect ratio format is the 14:9 format, since it is themathematical “halfway point” between a 4:3 standard screen image and a16:9 widescreen image. Since the active video does not fill the entirewidescreen frame, the broadcaster embeds black sidebars, also known ascurtains, at the edges of the frame to fill the 16:9 aspect ratio. The14:9 format is depicted in FIG. 3. Notice that in comparison to theimages shown in FIGS. 1-2, the hybrid aspect ratio is wider than astandard screen image but narrower than a true widescreen image.

Scan Mode

There are two ways to draw video images on a television or monitorscreen. The first method, the older of the two, is referred to as theinterlaced scan mode. In the interlaced scan mode, the image is drawn intwo separate passes. In the first pass, all of the odd “lines” of theimage are drawn from left to right and from top to bottom. In the secondpass, all of the even “lines” of the image are drawn from left to rightand from top to bottom. Each pass results in a portion of the imageknown as a field. Two fields combined together create a frame, which isthe entire image. All analog televisions drawn images on the screen inthis fashion.

Computer monitors were able to take advantage of advancements in CRTtechnology and in addition to using square pixels also adopted theprogressive scan modes. In the progressive scan mode, every line of theimage is drawn in a single pass, from left to right and from top tobottom. The frame is drawn all at once without dividing it into twoseparate fields as is done in the interlaced scan mode. This results inmuch less flicker in the video and smoother motion across the screen.Once again, in an effort to bring televisions and computer monitorscloser together, the ATSC has created a number of DTV formats that takeadvantage of the progressive scan mode. Since motion pictures are filmedand viewed in what is essentially a progressive scan format, the ATSCwanted to capture the “movie theater effect” in some of the DTV formatsas well. For backwards compatibility, several DTV formats still use theolder interlaced scan mode.

Frame Rate

As discussed above, the interlaced and progressive scan modes usedifferent methods to draw a complete picture frame on the screen.Interlaced scan methods draw a complete field every 60^(th) of a second,and since two fields are used to create a complete frame, the frame rateis equal to 30 frames per second (fps). The most common progressive scanrate is 60 fps, meaning that the complete image is drawn once ever60^(th) of a second. However, the ATSC has also defined additionalprogressive scan frame rates within the DTV standard. Most notable amongthese frame rates is the presence of 24 fps. This happens to be theframe rate at which motion pictures are filmed and presented in movietheaters. The film is projected onto the theater screen at a rate thatequals 24 complete picture frames every second. In an effort to provideDTV modes that capture the “movie theater effect” the ATSC definedseveral formats that use 24 fps progressive scan modes.

Aspect Ratio Mismatches

With the adoption of the ATSC DTV formats which include both 16:9 and4:3 aspect ratios, and the introduction of widescreen televisions toaugment the existing population of standard screen televisions, itbecomes readily apparent that viewing situations will arise when thetuned video program has an aspect ratio that is different from that ofthe television's display screen. The consumer electronics industry hasdeveloped techniques for handling these aspect ratio mismatches. Thesetechniques include:

-   -   Letterbox displays    -   Pillarbox displays    -   Stretch displays    -   Zoom displays

Televisions and set-top decoders apply these techniques in very specificscenarios that rely greatly on the DTV format of the tuned videoprogram. As a result, the formats in Table 1 will be referred toconstantly throughout this section, particularly the most common DTVformats which appear in the table shaded in gray.

Letterbox Displays

Letterbox displays are not new to the general viewing public. While someviewers may dislike the letterbox display format, almost everyone hasseen it at one time or another. The letterbox technique is used todisplay images on a television screen when the image itself has anaspect ratio that is wider than the display screen. The image is scaleddown in size (and resolution) until its width fits the physical width ofthe display screen. As a result, the image cannot fill the physicalheight of the display screen. In order to “frame” the picture on thescreen and reduce any visual distraction, the portions of the screenabove and below the image that are not filled with active video areusually set to black. The letterbox technique is depicted in FIG. 4,where the widescreen image from FIG. 1 is shown being displayed on a 4:3standard screen television.

The letterbox technique allows the viewer to see the entire video imageas it was originally filmed without any portions of the picture beingcropped and discarded in order to fill the entire screen. Whenever avideo that was originally filmed in a widescreen format is reformattedto fill a 4:3 standard screen television, portions of the image must becropped from each video frame. The full screen version of the widescreenimage as presented on the same 4:3 television is presented below in FIG.5.

A quick comparison of the television displays shown in FIGS. 4 and 5reveals that the letterbox technique effectively maintains the originalaspect ratio of the video program, but at the expense of lower pictureresolution and black static areas on the television screen. The fullscreen display does in fact fill the entire screen and takes advantageof the full vertical resolution of the television, but significantportions of the original video program must be cropped and cannot beenjoyed by the viewer. While some viewers wish to view widescreenprograms in their original aspect ratios regardless of any loss inresolution or the presence of static black bars, other viewers insistthat they have a full screen picture at all times even if it means theyare not able to view the entire image as originally filmed.

Referring to Table 1, it is clear that all HD formats are defined tohave an aspect ratio of 16:9. As a result, all 4:3 standard screen HDTVswill show HD programming in the letterbox format as seen in FIG. 4.There is no other way for a 4:3 television to show a widescreen image onits display screen. Whenever the television is fed with either 1080i or720p video signals, the display will automatically switch to theletterbox format with static bars above and below the active video.Given this information, it is easy to ask why do televisionmanufacturers even offer HDTVs that have 4:3 display screens. The reasonis fairly simple: the vast majority of television programming availabletoday is still in a 4:3 format, and these programs will fill the entirescreen of a 4:3 HDTV (as seen in FIG. 5) which is the expected behaviorby some viewers. However, all HD programming will have to be viewed inthe letterbox format on these sets.

Pillarbox Displays

The pillarbox display, unlike the letterbox display, is relatively newto the viewing public since the adoption of the ATSC DTV standard.Whereas the letterbox display is used to fit widescreen programming on a4:3 screen (though programs that are wider than 16:9 will also be shownas letterbox on a widescreen TV), the pillarbox format is used to fit4:3 programming on a widescreen display. Since a 4:3 image is too narrowto fill the width of a widescreen television, the television typicallywill center the image on the screen and place dark bars to the left andright of the image. A typical pillarbox display on a widescreen HDTV isdepicted below in FIG. 6. The image is centered and scaled vertically tofit the physical height of the display screen, and the portions of thescreen that are not filled with active video are usually set to black.

The pillarbox technique is one method used to display standard screen4:3 images on a widescreen display. Television manufacturers who makewidescreen HDTVs already know that the vast majority of televisionprogramming is still in the 4:3 aspect ratio. Therefore, themanufacturers have designed their widescreen televisions to work withstandard screen images in a number of ways. The only method to display4:3 content in its original aspect ratio without any distortion or videocropping on a widescreen HDTV is to apply the pillarbox format.

Stretch Displays

Widescreen television manufacturers took into consideration the factthat 90-95% of the content available on television today is 4:3. HDTVsuse a number of different display technologies, including cathode raytubes (CRTs), liquid crystals, plasma cells, and digital lightprocessing. Some of these display technologies are susceptible tophenomena known as “screen burn” and “screen fade.” This typicallyoccurs in phosphor-based display technologies such as CRTs and plasmacells. Referring to FIG. 6, and keeping in mind that 90-95% of thetelevision content today is still 4:3, it becomes clear that the leftand right sidebars will be present a great deal of the time. The centerportion of the television screen is constantly exercised and illuminated(and as such slowly fades in brilliance and clarity over time) but thesidebars remain unexercised and in a like-new state. This is known asscreen fade. When a widescreen image is finally displayed on the HDTV,the portion of the picture in the areas where the black sidebars usuallyreside will be noticeably brighter and crisper than the center area ofthe screen. A depiction of screen fade on a widescreen HDTV that hasbeen primarily used to watch 4:3 video in the pillarbox format is shownbelow in FIG. 7.

Most widescreen HDTV manufacturers recommend (particularly on expensiveplasma displays and any CRT-based display) that the pillarbox format beused for less than 20% of total viewing. Since 90% or more of thecontent available today is in 4:3 format, widescreen HDTVs have beendesigned with several ways of “fitting” 4:3 video to their 16:9 screens.These methods include the stretch display, which will be discussed here,and the zoom display, which will be discussed in the next section.

Most widescreen HDTVs have implemented one or more types of stretchmodes. These modes allow the viewer to fill the 16:9 screen with activevideo so that no static black bars reside on the display. The reason forthis is twofold: the potential for screen fade is greatly reduced whenthe pillarbox display mode is used less frequently, and some viewersactually prefer to always have video fill their entire television screenregardless of any distortion or cropping that takes place. In discussingany kind of stretch mode on a widescreen HDTV, the industryunderstanding is that the stretch only takes place in the horizontaldirection and that there is no processing that takes place in thevertical direction. Zoom modes, which are discussed in the next section,apply horizontal and vertical processing to fit the video to the displayscreen. In general, stretch modes imply processing along the horizontalwidth of the screen only.

There are a number of ways to perform a horizontal stretch of an imageon a widescreen display. Television manufacturers use the quality oftheir stretch and zoom modes as key differentiators in the marketplace.While the complexity of the stretch algorithms varies greatly betweenHDTV models, fundamentally stretch modes are implemented using linearprocessing or nonlinear processing.

-   -   Linear stretch—Horizontal distortion is uniform across the        entire image    -   Nonlinear stretch—Horizontal distortion is focused on the edges        of the image

An example of a linear stretch mode is depicted below in FIG. 8. In thisexample, the 4:3 content that is shown in FIG. 6 is linearly stretchedby the widescreen HDTV to fill the entire display.

A comparison of FIGS. 6 and 8 shows some of the horizontal distortionthat occurs when a linear stretch mode is invoked by the HDTV. The whitehouse in the center of the picture is much wider than it would appear ifviewed in person (or in the pillarbox format which preserves the properaspect ratio). For inanimate objects, such as the house in this picture,the distortion that is introduced by the HDTV does not look that odd tothe human eye. However, scenes that contain human beings (andparticularly human faces) can look very strange to the human eye whenviewed in a stretch mode, since we have fairly fixed notions of what a“normal” human being or human face looks like. When stretched to fill awidescreen HDTV, humans on-screen can look very distorted and canimmediately cause the reaction that there is excessive distortion in thepicture, even more than if the exact same stretch method is applied to ascene containing inanimate objects such as in FIG. 8.

Zoom Displays

In addition to the stretch modes (linear and nonlinear) that widescreentelevision manufacturers have implemented on their products, analternate display mode known as a “zoom display” has started to appearwith increasing frequency on many widescreen HDTV sets. The zoom mode isbasically a two-dimensional stretch. The image is stretched horizontallyto fill the width of the display screen, but is also stretchedvertically so that the amount of horizontal distortion is greatlyreduced. However, once-viewable portions of the picture at the top andbottom are in effect “zoomed” off the screen and are basically cropped.

The zoom display is an alternative to the basic stretch display thatsome viewers may not enjoy because of the horizontal distortion that isintroduced, particularly when viewing people in this manner. The zoomdisplay stretches the picture in both directions, though depending onthe manufacturer, the amount of stretch in both directions may be verysimilar or very different. An example of a zoom mode (where equalamounts of stretch are applied horizontally and vertically) is shownbelow in FIG. 9.

To see the difference between the zoom display and the stretch display,compare the television displays in FIGS. 8 and 9. There are severalnoticeable differences between the two images. To illustrate thesedifferences, compare the white house in the center of the picture, thestreet sign on the left of the picture, and the concrete post at thelower left of the picture. In the zoom display, the house and the signhave no appearance of horizontal distortion and appear in the normal(original) aspect ratio. This appears to be an advantage over the linearstretch display. However, it can also be seen that the chimney of thewhite house is much closer to the top of the display screen and asizable portion of the concrete post has disappeared from the displayscreen entirely. Portions of the top and bottom of the original imageare therefore cropped from view and cannot be seen by the viewer. Whilein this scene the effect of losing the upper and lower portions of thescreen is negligible, scenes that focus on “close-ups” on dialogue andsuch may crop signification portions of the actors' faces and heads fromview. Some viewers may find that to be visually disruptive and mayprefer to watch those scenes in a stretch display or a pillarboxdisplay. The choice is left to the viewer to decide what they believe“looks best” and the widescreen HDTV manufacturers have attempted toprovide a number of options to suit the various preferences of theviewers.

ASTB Video Output Formats

The Advanced Set-top Boxes (ASTBs) are equipped with a number of videooutputs. These outputs include component video ports, an s-video port, acomposite video port, and an RF output. Since the component video portsare intended to be the primary connection used with an HDTV, and themajority of the proposed video features deal with DTV formats (which thecomponent video ports alone can accommodate), the embodiments hereinwill focus on the component video (YPbPr) outputs.

An exemplary embodiment of a set top box, such as the DCT-5100, iscapable of generating video outputs in any one of five different ATSCDTV formats. These formats are shown in Table 1 shaded in gray and arereferred to as 1080i, 720p, 480p (16:9), 480p (4:3), and 480i. Thenumeric portion of the video format refers to the number of verticalpixels, the “p” refers to the progressive scan mode, and the “i” refersto the interlaced scan mode. Each of these formats has a single definedaspect ratio except for the 480p format. The aspect ratio restrictionsare depicted FIG. 10.

FIG. 10 depicts the aspect ratios that are defined for each of the fiveDTV output formats included in the exemplary embodiment of an ASTB.Therefore, it is impossible for this embodiment to generate a 1080i 4:3picture, for example. Since these five DTV formats are the only formatsavailable on the component video outputs of the DCT-5100, any proposedvideo features will essentially boil down to a generated video output inone of these five formats. It is essential to understand how differentHDTVs (widescreen and standard screen) display each of these five DTVformats in order to understand the resultant output that will begenerated by each proposed video feature. For example, many widescreenHDTVs automatically stretch 480p signals to fill the display screen,regardless of whether the video source signal has a 4:3 480p format or a16:9 480p format. The reason that the televisions do this is fairlystraightforward: 480p is the output format generated by all progressivescan DVD players, and the TV manufacturer assumes that if the consumerhas purchased a widescreen television, the consumer must also bewatching widescreen (anamorphic) DVDs with their progressive scan DVDplayer. As a result, the television stretches the 480p signal to fillthe screen, which is the proper choice when viewing anamorphic DVDs on aprogressive scan DVD player. However, this “auto-stretch” by thewidescreen TV may produce a very different effect from the one desiredfrom the exemplary embodiment.

Current ASTB User Settings

The exemplary embodiment of the ATSB provides to the consumer a “UserSettings” screen that allows the consumer to configure the ASTB to workwith their specific model of HDTV and set some general viewingpreferences. An exemplary embodiment of an ASTB configuration menu isshown below in Table 2. The default values for each option as defined inthe ASTB firmware are shown first (16:9, 1080i, 480i) and the additionalvalues that can be selected are shown in parentheses. TABLE 2 USERSETTINGS TV TYPE 16:9 (4:3 LETTERBOX, 4:3 PAN-SCAN) YPbPr OUTPUT 1080i(720p, 480p, 480i) 4:3 OVERRIDE 480i (480p, OFF) CLOSED CAPTION DISABLEDOPTIONS: PEN SIZE AUTO FONT STYLE AUTO FOREGROUND COLOR AUTO FOREGROUNDOPACITY AUTO BACKGROUND COLOR AUTO BACKGROUND OPACITY AUTO SERVICESELECTION AUTO SETTINGS AUTO RESTORE DEFAULTS

The three options used primarily for configuring the ASTB are known asTV Type, YPbPr Output, and 4:3 Override. These options allow theconsumer to configure the exemplary embodiment of the ATSB to work withtheir particular model of HDTV and control the manner in which SD and HDcontent in viewed on the HDTV. The options perform the followingfunctions:

-   -   TV Type—Specifies the type of HDTV connected to the ASTB.    -   YPrPb Output—Specifies the output video format on the set-top's        component video ports except when the 4:3 Override is in effect.    -   4:3 Override—Specifies the output video format on the set-top's        component video ports when the ASTB is tuned to a 4:3 program.

The 4:3 Override feature is one type of automatic output switching andaddresses a number of issues such as postage stamped displays and screenburn/fade.

One of the advantages of the exemplary embodiment of the User Settingsscreen is that it has been designed with a “set and forget” approach,meaning that once the consumer finds the selections that work best withhis/her particular model of HDTV, there is never a need to go back intothe menu to change settings. As a result, the driving requirement forany addition that is to be made to the User Settings screen is that itmust be implemented as a “Set And Forget” style option.

Video Features

The embodiments of the ATSB implement various stretch and zoom modes toprovide more viewing options to the consumers and to counteract staticblack areas embedded in HD programs by some broadcasters.

ASTB 4:3 Stretch Mode

The exemplary embodiment of the ATSB incorporates some type of stretchmode for viewing true 4:3 programs on a 16:9 widescreen HDTV. Thisfeature can be provided in addition to the standard 4:3 Overridefeature, and therefore can be implemented in such a fashion as to becomplementary to the 4:3 Override feature. The ASTB Stretch Mode is notintended to be used with 4:3 content that is broadcast in a 16:9 formatin the pillarbox mode.

Assumptions

The assumptions that were made in order to come up with the embodimentsherein for implementation of the ASTB Stretch Mode are listed below.

-   -   The Stretch Mode should apply to consumers with 16:9 HDTVs    -   The Stretch Mode should not apply to consumers with 4:3 HDTVs    -   The Stretch Mode should augment the 4:3 Override Feature    -   The Stretch Mode should be invoked when the ASTB is tuned to 4:3        content    -   The Stretch Mode should not be invoked when the ASTB is tuned to        16:9 content

On widescreen HDTVs, the stretch modes are used to fill the 16:9 screenwith 4:3 video content. The stretch algorithms can vary, but the finalresult is a filled display screen. Standard television screens with 4:3aspect ratios have no need for a stretch feature because the displayscreen matches the aspect ratio of 4:3 video content. Since the 4:3Override feature is a standard feature on the ASTB product line, and anyASTB Stretch Mode would also deal with 4:3 video content, the StretchMode should be implemented in a complimentary fashion to the 4:3Override.

Problems Addressed

The problem that this feature primarily addresses is any widescreentelevision that either does not have its own stretch mode for viewing4:3 full screen, or a widescreen television that does a poor job ofcreating stretch displays. By incorporating this feature on theexemplary embodiments of ASTBs, the set-top boxes provide yet anotherviewing option that will enhance the feature set of the product andpotentially improve the viewing experience of the consumer.Additionally, widescreen televisions that use phosphor-based displaytechnologies are susceptible to screen burn & fade. The implementationof a stretch feature on the ASTB also serves to provide a safeguardagainst possible screen damage to a costly HDTV.

Exemplary Embodiment

The ASTB 4:3 Stretch Mode is not envisioned to be a frequently-toggledfeature like the ASTB 16:9 Zoom Mode. It is envisioned that the consumerwill use the ASTB Stretch Mode on a widescreen HDTV if either thewidescreen HDTV itself does not supply a stretch mode or if the HDTVdoes a poor job with its stretch display. In that case, the consumer hasthe option of using the ASTB to perform the stretch instead.

Since most television manufacturers recommend viewing content thatcauses static black areas on the screen (such as pillarbox displays)less than 20% of the time to reduce any chance of screen fade, it islikely that the ASTB 4:3 Stretch Mode will not be toggled on and offfrequently by the consumer. If the consumer decides to use the ASTBStretch Mode, it will likely become the default mode for viewing 4:3content on a 16:9 widescreen HDTV. If the consumer prefers the stretchmodes offered by the HDTV, then the standard ASTB 4:3 Override featurewill be used to provide 4:3 video formats to the HDTV to stretch on itsown.

Due to the likelihood that the ASTB Stretch Mode will be an “all ornothing” type of feature, meaning that the consumer will either use itthe majority of the time or hardly at all, it is not critical that thisfeature be toggled from a remote control button. Though a remote controlbutton provides a cleaner user experience to toggle the stretch featureon and off, as opposed to entering the User Setting screen and togglingthe feature there, it is not deemed to be an absolute necessity in orderto implement the ASTB Stretch Mode Feature.

The ASTB Stretch Mode can be added neatly and intuitively to the 4:3Override menu selection in the User Settings screen. A “STRETCH” optioncan appear as an additional option next to 480i, 480p, and OFF. Sincethis feature is intended only for widescreen HDTVs, the STRETCH optionunder 4:3 OVERRIDE can be made so that it is only accessible if the TVTYPE is set to 16:9. If the TV TYPE is set to 4:3 (either Letterbox orPan Scan) then the ASTB Stretch Mode should not be accessible as itprovides no advantage over the existing 4:3 Override feature.

The exemplary embodiments of the ATSB can be configured so that theprimary output format, set via the YPrPb OUTPUT menu option, is one ofthe two available HD formats (720p or 1080i). In these cases, theSTRETCH option should be available as one of the 4:3 OVERRIDE settings.Additionally, the STRETCH option should be available if the YPrPb OUTPUTis set to 480p. Currently, if the YPrPb OUTPUT is set to 480i, the 4:3OVERRIDE automatically switches to OFF and becomes inaccessible. Thissame behavior should continue with the addition of the ASTB StretchMode, since in this instance the consumer has forced the ASTB to outputa known 4:3 video mode in 480i and there is no need for the stretchmode.

The addition of the STRETCH option to the 4:3 OVERRIDE submenu is shownin Table 3. In the exemplary embodiment, the STRETCH feature is toggledfrom the User Settings screen and is enabled whenever the ASTB is tunedto true 4:3 content. In effect, the ASTB 4:3 Stretch Mode becomes anaugmentation of the standard 4:3 Override feature that is easily turnedoff and on by the consumer by accessing the User Settings display. TABLE3 Addition of the ASTB Stretch Mode to the User Settings Menu USERSETTINGS TV TYPE 16:9 (4:3 TVs have no need to view 4:3 video stretched)YPbPr OUTPUT 1080i, 720p, or 480p (480i defaults the 4:3 Override toOFF) 4:3 OVERRIDE STRETCH (the consumer can still choose 480i, 480p, orOFF)

The ASTB 4:3 Stretch Mode can then be instantiated whenever the ASTB istuned to a 4:3 service, regardless of whether it was an analog serviceor a digital service. The ASTB can recognize that it had been tuned to a4:3 service, stretch the 4:3 video to fill a 16:9 viewing frane, andoutput the resultant widescreen video in the output format specified bythe YPbPr OUTPUT setting in the User Settings screen. An exemplaryembodiment of a logical process that would be invoked after a channelchange is shown in FIG. 19.

In step 101, a user-selected channel is tuned to.

In step 102, the determination is made if the service is a 4:3 service.If the service is not a 4:3 service, in step 104 the YPrPb OUTPUT formatis used and the process ends. If the service is a 4:3 service, theprocess moves to step 103, in which the override setting is determined.

If the override setting is not set to STRETCH, in step 105, the existinglogic for the 4:3 Override feature is applied and the process ends. Ifthe override setting is set to STRETCH, the process moves to step 106,in which the 4:3 video is stretched to fill a 16:9 frame. Thisstretching function can be a linear stretching function or a non-linearstretching function.

In step 107, any overlaying graphics (such as electronic programmingguide information or closed-captioning text) is not stretched to avoiddistortion.

In step 108, the video is converted to the output format specified bythe YPrPb OUTPUT setting. For example, if the YPrPb OUTPUT setting is1080i (determination made in step 109), the stretched video is 1080i(step 112). If the YPrPb OUTPUT setting is 720p (determination made instep 110), the stretched video is 720p (step 113). And, if the YPrPbOUTPUT setting is 480p (determination made in step 111), the stretchedvideo is 480p (step 114).

In step 109, the stretched and converted video frames are output on thecomponent video outputs. Only the primary High Definition video outputs(YPrPb) include stretched video frames. The secondary standard digitalvideo outputs (e.g., Composite, S-Vid, RF) include 4:3 video.

One embodiment of the ASTB Stretch Mode utilizes a linear stretchalgorithm, while others may utilize nonlinear stretch algorithms.Nonlinear stretch algorithms can reduce the perceived amount ofdistortion by the viewer and promote a more enjoyable viewingexperience.

Advantages

There are some inherent advantages to this particular implementation ofthe ASTB Stretch Mode.

Advantages:

-   -   The ASTB Stretch Mode fits very neatly into the “Set And Forget”        theme of the User Settings menu as one of the selectable ways to        watch 4:3 content.    -   The ASTB Stretch Mode does not force a switch of the YPrPb        output format, so there is no visible re-synch that must occur        on the HDTV to reacquire and display the new format.    -   The ASTB Stretch Mode can be augmented to include several        different stretch algorithms if necessary (linear and nonlinear        methods) that drop neatly into the User Setting    -   The ASTB Stretch Mode would automatically protect expensive        widescreen HDTVs from damage caused by screen bum and screen        fade since it would be invoked as soon as the set-top tuned to        known 4:3 content.

Drawbacks:

-   -   The ASTB Stretch Mode cannot provide an “instant gratification”        toggle for the consumer without a new remote control key.

Overall, it appears that the proposed implementation offers even moreviewing options for consumers who own widescreen HDTVs and can help toreduce the chance of causing damage to any phosphor-based displays. Someconsumers may decide that they do not like the way that the set-topperforms the stretch based on their own personal viewing preferences,but since the ASTB 4:3 Stretch Mode is not a default setting and can beeasily turned off, this is not an issue.

ASTB 16:9 Zoom Modes

The exemplary embodiments of the ATSB incorporate some type of zoomfeature for viewing widescreen 16:9 broadcasts that have hybrid aspectratio video. This feature would be provided in addition to the standard4:3 Override feature, and therefore is implemented in such a fashion asto be complementary to the 4:3 Override feature. The ASTB Zoom Modes areintended to provide the consumer with several different options forviewing hybrid aspect ratio programming.

Assumptions

The assumptions that were made in order to come up with the proposedimplementation of the ASTB 16:9 Zoom Modes are listed below.

-   -   The Zoom Modes should apply to consumers with 16:9 HDTVs    -   The Zoom Modes should apply to consumers with 4:3 HDTVs    -   The Zoom Modes should complement the 4:3 Override Feature    -   The Zoom Modes should be toggled via remote control    -   The Zoom Modes should not be toggled via the User Settings menu    -   The Zoom Modes should be selectable when the ASTB is tuned to        16:9 content    -   The Zoom Modes should not be selectable when the ASTB is tuned        to 4:3 content since this case is covered by the 4:3 Override        and ASTB Stretch features

The ASTB Zoom Modes will be used primarily to fill the entire displayscreen on 16:9 HDTVs and as much of the display screen as possible on4:3 HDTVs whenever the tuned HD programming contains static black areasembedded in the video. The vast majority of television content recordedover the last 5 decades has been in the standard screen 4:3 aspectratio. There is not yet enough true widescreen 16:9 HD programming for aDTV broadcaster to fill an entire day, so often the older 4:3 content isupconverted to a DTV format and broadcast with black sidebars (known asthe pillarbox display) to fill the required 16:9 video frame for an HDtransmission.

Problems Addressed

The ASTB 16:9 Zoom Modes can offer viewers several different optionswhen viewing HD broadcasts that do not have a full 16:9 frame worth ofactive video. The video is narrower than the 16:9 broadcast frame, andin order to comply with the 16:9 aspect ratio requirement specified bythe ATSC DTV standard, static black bars are placed to the left and theright of the video to fill the width of the 16:9 frame (see FIG. 5).Static black bars that are embedded in the broadcast are typically ofgreat concern to HDTV owners because until now there has been no way tocounteract them. There are two reasons why a viewer would like to beable to counteract the embedded black bars in a widescreen broadcast: 1)they prefer to view “fullscreen” displays as often as possible anddislike any static black areas, or 2) the black areas can contributeover time to a phenomenon known as “screen burn” or “screen fade” whichcan damage an HDTV display, particularly the very costly plasma HDTVs.

Exemplary Embodiment

Since the ASTB Zoom Modes would in all likelihood be toggled by theviewer as he/she flips through the available channels to suit theprogram they have selected at that moment, a static menu setting such asthe one used for the ASTB Stretch Mode would not be practical. Thiswould force the viewer to enter the User Settings screen every time theytuned to a hybrid aspect ratio program which the viewer wished “to zoom”in some fashion. In order for the ASTB Zoom Modes to work intuitivelyand in a fashion consistent with the rest of the consumer electronicsindustry, the zoom modes must be toggled via the remote control.

In studying the most common hybrid aspect ratios used by DTVbroadcasters today, the three used most often are the 15:9 hybrid, the14:9 hybrid, and the 4:3 hybrid. In these cases, all of the video framesare in fact 16:9, yet the frames are filled with (centered) video thatis either 15:9, 14:9, or 4:3. Since all three of these aspect ratios arenarrower than 16:9, static black bars appear to the left and the rightof the active video to center it within a 16:9 video frame. Examples ofthese three common hybrid aspect ratio broadcasts are depicted in FIG.11. The static black areas to the left and right of the active video areactually part of the total video frame that is being transmitted by thebroadcaster.

The ASTB 16:9 Zoom Modes should provide some benefit to consumers whoown either a widescreen 16:9 HDTV or a standard screen 4:3 HDTV.Although the consumers who own the more expensive widescreen TVs whichare more susceptible to screen burn and screen fade have more to gainfrom the implementation of the ASTB Zoom Modes, viewers with 4:3 HDTVsshould also benefit from these zoom modes. However, since 16:9 HDTVs and4:3 HDTVs display widescreen programming in very different fashions, theASTB Zoom Modes should be implemented so that they behave differentlyfor 16:9 HDTVs and 4:3 HDTVs.

ASTB 16:9 Zoom Modes on Widescreen HDTVs

Through the TV TYPE setting in the User Settings screen, the ASTB candetermine that it is connected to either a 16:9 HDTV or a 4:3 HDTV.Using this information, the ASTB can tailor the ASTB Zoom Modes to whatmakes the most sense for the particular television connected to it. Inthe case of the widescreen HDTVs, the ASTB 16:9 Zoom Modes should beable to counteract the three commonly encountered hybrid display formatsshown in FIG. 11. Since the 15:9 and 14:9 hybrid formats are so similarto each other in terms of width, there is little need to have a zoommode to support the 15:9 format and a separate mode to support the 14:9format. A zoom mode to support the 14:9 format alone will also handlethe 15:9 format as well, though there will be very slender strips ofvideo cropped off the screen in the 15:9 hybrid scenario. The 15:9 and14:9 formats are fairly close in width to the full 16:9 video frame.While the term “zoom” in the consumer electronics industry typicallyimplies a two dimensional stretch of an image horizontally andvertically (to reduce distortion in any one direction), the 15:9/14:9zoom mode would implement a “horizontal-only” stretch to fill the entire16:9 frame with active video with very little horizontal distortion (asopposed to stretching a 4:3 image to fill a 16:9 frame).

The 4:3 hybrid aspect ratio is quite a bit narrower than the 15:9 and14:9 hybrid formats and as a result should be handled by two different“zoom” formats. The first mode would perform a horizontal stretch of the4:3 video to fill the 16:9 frame. The second mode would apply horizontaland vertical stretch to fill the width 16:9 video frame with little orno distortion, but there would be some cropping of the top and bottom ofthe original video image as it was stretched vertically to minimizehorizontal distortion.

To summarize, exemplary embodiments of ASTB Zoom Modes for a widescreen16:9 HDTV would include four selectable zoom modes that can be cycledthrough using the remote control and would “wrap” around to the top ofthe list with consecutive remote control button presses:

-   -   16:9 Zoom Mode #1: A “No Zoom” mode to remove all ASTB Zoom Mode        processing to view the broadcast “as is.”    -   16:9 Zoom Mode #2: A zoom mode that takes a centered 14:9 cutout        of the 16:9 broadcast and horizontally stretches it to fill a        16:9 frame.    -   16:9 Zoom Mode #3: A zoom mode that takes a centered 4:3 cutout        of the 16:9 broadcast and horizontally stretches it to fill a        16:9 frame.    -   16:9 Zoom Mode #4: A zoom mode that takes a centered 4:3 cutout        of the 16:9 broadcast and horizontally and vertically stretches        it to fill a 16:9 frame.        ASTB 16:9 Zoom Modes on Standard Screen HDTVs

Through the TV TYPE setting in the User Settings screen, the ASTB candetermine that it is connected to either a 16:9 HDTV or a 4:3 HDTV.Using this information, the ASTB could tailor the ASTB Zoom Modes towhat makes the most sense for the particular television connected to it.In the case of the 4:3 standard screen HDTVs, the ASTB Zoom Modes shouldbe able to counteract the three commonly hybrid aspect ratios shown inFIG. 11. However, 4:3 HDTVs are not designed to display 16:9 broadcastsas full screen images like the widescreen HDTVs are. As a result, every4:3 HDTV available today must display 16:9 widescreen programming in theletterbox format (see FIG. 4). Whenever a 4:3 HDTV is fed with a 1080ior 720p input signal, which it understands to use the 16:9 aspect ratio,it will automatically switch to a letterbox type of display. This is animportant fact to keep in mind when discussing the ASTB Zoom Modes for a4:3 HDTV.

Hybrid aspect ratio broadcasts will display as a “postage stamp” displayon a 4:3 HDTV. Where a 16:9 widescreen TV would only display the blackbars on the left and right of the active video, a 4:3 standard screen TVwould display black bars on all four sides of the active video. Thisoccurs because the broadcaster has embedded black bars to the left andthe right of the active video to fill a 16:9 video frame, and the 4:3HDTV must use the letterbox display with black bars above and below theactive video to fit the widescreen program to its standard screendisplay. This limits the effectiveness of the ASTB 16:9 Zoom Modesdiscussed for widescreen HDTVs previously because a 4:3 HDTV wouldalways show black bars above and below the active video as a result ofits own letterbox requirements. The zoom modes discussed for widescreenHDTVs would eliminate the postage stamp display on a 4:3 HDTV, but noneof them could counteract the letterbox display.

In order to provide a degree of usefulness in the ASTB 16:9 Zoom Modesfor owners of 4:3 HDTVs, an additional zoom mode that is only availablefor 4:3 HDTVs could be made available. It would provide the viewer witha fullscreen display, but at the cost of definition and panorama.Essentially, the final zoom mode designed for 4:3 HDTVs would force theASTB output to a known 4:3 video format (either 480i or 480p) anddisplay a centered 4:3 cutout of the 16:9 video frame on the screen.This would be the equivalent of a “cropped” display as opposed to a pan& scan display. The 4:3 cutout would be centered on the 16:9 videoframe. Since the zoom modes are intended to counteract the hybrid aspectratios with black areas to the left and right of the screen, the amountof active video that is actually being “cropped” in this case may bevery little (for the 15:9 and 14:9 cases) or none at all (for the 4:3case). This provides the 4:3 HDTV viewer with a level of functionalitythat is particularly useful for their television displays.

To summarize, an exemplary embodiment of ASTB Zoom Modes for awidescreen 16:9 HDTV would include four zoom modes that can be cycledthrough using the remote control:

-   -   4:3 Zoom Mode #1: A “No Zoom” mode to remove all ASTB Zoom Mode        processing to view the broadcast “as is.”    -   4:3 Zoom Mode #2: A zoom mode that takes a centered 14:9 cutout        of the 16:9 broadcast and horizontally stretches it to fill a        16:9 frame.    -   4:3 Zoom Mode #3: A zoom mode that takes a centered 4:3 cutout        of the 16:9 broadcast and horizontally stretches it to fill a        16:9 frame.    -   4:3 Zoom Mode #4: A zoom mode that takes a centered 4:3 cutout        of the 16:9 broadcast and converts the output format of the ASTB        to a known 4:3 format (either 480i or 480p).

If the ASTB 4:3 Stretch Mode is implemented as well, then there is thepossibility that the 4:3 OVERRIDE could be set to STRETCH in certaincases. Since it has been proposed that the ASTB 16:9 Zoom Modes utilizethe 4:3 OVERRIDE setting in certain cases to decide what format outputto generate to display on the HDTV, it is worthwhile to cover thisscenario in a bit more detail. The ASTB 4:3 Stretch Mode is intended foruse by consumers who own widescreen 16:9 HDTVs only. There is no needfor a stretch feature for 4:3 standard screen HDTVs. As a result, the4:3 OVERRIDE option can only be set to STRETCH if the TV Type is 16:9.Likewise, the zoom modes tailored to a 4:3 HDTV are only invoked via theremote control if the 4:3 OVERRIDE option is set to either 4:3 Letterboxor 4:3 Pan-Scan. In this case, the “STRETCH” option is not accessiblefor the 4:3 OVERRIDE menu and they only available options are 480i,480p, or OFF. The logical process covers the expected behavior for eachof these three allowable settings.

Logical Process for the ASTB 16:9 Zoom Modes

The exemplary embodiment of the ASTB 16:9 Zoom Mode feature is a complexfeature that provides a great amount of control to the viewer over howthey wish to view 16:9 programming on their HDTV. The ASTB 16:9 ZoomModes are envisioned primarily to allow the viewer to remove staticblack areas embedded in a 16:9 broadcast in order to provide a morepleasant viewing experience or to reduce the possibility of screendamage to a costly widescreen HDTV.

An exemplary embodiment 200 of a logical process for the ASTB 16:9 ZoomMode feature as follows would be invoked via a remote control buttonpress is shown in FIG. 20.

In step 201 a zoom mode toggle command is received from the remotecontrol, after which in step 202 a determination is made as to whetherthe currently tuned service is a 16:9 broadcast. If the service is not a16:9 service, then the zoom toggle is ignored in step 205 and theprocess ends. If the service is a 16:9 service, then the zoom toggle isallowed and the process continues.

In step 203, the TV TYPE setting is determined from the User Settingsscreen entered via a graphical user interface.

If the TV TYPE is 16:9, in step 206, each toggle press moves to the nextmode available for that TV Type, and in step 207 the output format isset to the mode specified by the YPrPb OUTPUT. The process then ends

If the TV TYPE is 4:3 Letterbox or 4:3 Pan Scan, in step 208 each togglepress moves to the next mode available for that TV Type.

In step 209, the determination is made as to whether the fourth zoommode is selected (i.e., 4:3 Zoom Mode #4: A zoom mode that takes acentered 4:3 cutout of the 16:9 broadcast and converts the output formatof the ASTB to a known 4:3 format (either 480i or 480p)). If not, instep 211 the output format is set to the mode specified by the YPrPbOUTPUT and the process ends. If so, the output format is set to the modespecified by the 4:3 override setting.

The 4:3 OVERRIDE format provides a means for the ASTB 16:9 Zoom Modefeature to know what the user's preference is for viewing 4:3 video ontheir 4:3 HDTV. If the user has selected 480i, then the 4^(th) zoom modefor 4:3 HDTVs should output the cropped video in the 480i format. If theuser has selected 480p, then the 4^(th) zoom mode for 4:3 HDTVs shouldoutput the cropped video in the 480p format. If the user has selectedOFF, then the ASTB 16:9 Zoom Mode feature should toggle automatically tothe 1^(st) zoom mode for 4:3 HDTVs (which is the “no zoom” mode).

Graphical Representation of the ASTB 16:9 Zoom Modes

Since a picture is worth a thousand words, and it can be difficult tovisualize the displays that will result on the HDTV screen as the usercycles through the zoom modes, several tables in the figures depict theresulting displays on the television screen for each combination of HDTVtype (widescreen or standard screen), hybrid aspect ratio broadcastformats, and ASTB Zoom mode.

FIG. 12 contains three images that will be used to represent the threepopular hybrid aspect ratio formats that are commonly used bybroadcasters today. Each image represents a specific broadcast format.From left to right these images represent the 15:9 hybrid aspect ratioformat, the 14:9 hybrid aspect ratio format, and the 4:3 hybrid aspectratio format respectively. These images will be used in FIGS. 13-18 toshow that the set-top has tuned to a program that is being broadcast inone of these three hybrid formats.

FIGS. 13-18 depict the displays that are produced on an HDTV screen whenthe user cycles through the various ASTB 16:9 Zoom Modes for each of thethree popular hybrid aspect ratio formats shown above. FIGS. 13-15 showthe displays produced on a widescreen (16:9) HDTV. FIGS. 16-18 show thedisplays produced on a standard screen (4:3) HDTV. Note that the tablesdo not show the displays for Zoom Mode #1, which is the “no zoom” modeand has no effect on the display that is produced on the HDTV screen,which is the version shown as the tuned program in each figure.

Advantages

There are some inherent advantages to this exemplary embodiment of theASTB 16:9 Zoom Mode feature.

-   -   The ASTB Zoom Mode feature is tailored to provide benefits to        owners of both style of HDTV (16:9 and 4:3).    -   The ASTB Zoom Mode feature can provide “instant gratification”        with a remote control button press.    -   The ASTB Zoom Mode feature can counteract static black bars        embedded by broadcasters which could damage expensive widescreen        HDTVs over time.    -   The ASTB Zoom Mode feature offers several different modes to        accommodate a range of viewer preferences.    -   The ASTB Zoom Mode feature utilizes the options selected in the        User Settings menu to enhance the logical process.

Overall, the exemplary embodiment offers even more viewing options forconsumers who own widescreen and standard screen HDTVs and can help toreduce the chance of causing damage to any phosphor-based displays,particularly the expensive widescreen televisions. Consumers who own 4:3HDTVs can fully eliminate the “postage stamp” display at any time with acouple of remote control button presses. Some consumers may decide thatthey do not like the way that the set-top applies the zoom processingbased on their own personal viewing preferences, but since the ASTB ZoomMode is not a default setting and can be easily toggled using the remotecontrol, this is not an issue.

ASTB 4:3 Stretch Feature Support

The existing ASTB hardware (such as BCM 7035) is capable of supportingthis feature on the primary video outputs (YPbPr or DVI) of the set-topbox. The 7035 supports linear scaling factors, but linear and non-linearscaling factors can be used in other exemplary embodiments. The ASTB 4:3Stretch feature may be augmented to take advantage of the non-linearscaling capabilities.

The video quality that will result on the secondary video outputs(s-video, composite, and RF) can be affected when the stretch feature isin use. In one embodiment, the stretch processing is applied to the mainvideo pipeline for presentation over the primary video outputs. In thiscase, the video for the secondary outputs needs to be “de-stretched”before presentation on the secondary video outputs.

ASTB 16:9 Zoom Feature Support

The existing ASTB hardware (BCM 7035) is capable of supporting thisfeature on the primary video outputs (YPbPr or DVI) of the set-top box.The 7035 supports linear scaling factors that may be appliedhorizontally and/or vertically to provide a simple “stretch” effect or atwo-dimensional “zoom” effect. The exemplary embodiment takes a centered“cutout” of a 16:9 frame and applies the scaling factors to that cutout.Once that cutout has been made (either 14:9 or 4:3 depending on the zoommode), then the application of the horizontal and/or vertical scalingfactors is a relatively straightforward process.

The video quality that will result on the secondary video outputs(s-video, composite, and RF) may be affected when the stretch feature isin use. As in the above-mentioned embodiment, the zoom processing isapplied to the main video pipeline for presentation over the primaryvideo outputs. The video for the secondary outputs needs to be“de-zoomed” before presentation on the secondary video outputs. Thesecondary outputs would also need to show a different style of outputthan the primary video outputs due to the inherent video cropping thattakes place in the zoom modes (for example, the primary outputs maypresent a zoomed 4:3 image whereas the secondary outputs may be expectedto present a 4:3 letterboxed output).

FIG. 21 depicts an exemplary embodiment 230 for implementing the aboveprocesses and methods. A set-top box 220 receives the incoming videofrom a cable or other source. A video processor 221 performs theabove-mentioned processes based on programming stored in its memory 222.The converted video is output to a display 225. A remote control 226activates the zoom toggle feature discussed above via a receiver 223 inthe set-top box 220. A graphical user interface 224 interacts with theuser to set the television type and other settings mentioned above.

In general, using the present invention a high definition capable settop receiver is informed of the aspect ratio of the TV it is connectedto (4:3 or 16:9), and using this information the set top receivermanipulates the received video image using stretch/zoom techniques. Themanipulated video image is then output to the display using one or moreATSC formats. The set top receive receives input from the user via frontpanel, RF, or IR remote control, for example, to select one or more zoommodes. The set top receiver will provide at least one customized zoommode guaranteed to fill the entire screen of display or television towhich the set to receiver is connected. The set top receiver will alsoprovide additional zoom modes that are agnostic or independent of theaspect ratio of the display or television to which the set top receiveris connected. The set top receiver will then select the appropriatecustomized zoom mode automatically based on the aspect ratio of thedisplay or television without requiring additional input from the user.

An exemplary embodiment of a method 240 for controlling the display ofan image in a video signal being output to a display is shown in FIG.22. The set top receiver receives information as to an aspect ratio ofthe display to which the set-top receiver is connected (step 241). Theset top receiver then manipulates the received video image using astretch/zoom technique to provide at least one customized zoom modeguaranteed to fill an entire screen of the display, as well as toprovide one or more additional zoom modes that are independent of theaspect ratio of the display (step 242). The manipulated video image isoutput to the television or display using one or more ATSC formats (step243). Input from a viewer is then used to select one of the at least onecustomized zoom mode or the one or more additional zoom modes (step244). In the case of no input from the viewer, the zoom mode is setautomatically based on the aspect ratio of the display without requiringadditional input from the user (step 244).

SUMMARY

The present invention includes exemplary embodiments implementing theASTB Stretch Mode and the ASTB Zoom Mode features for the set-top boxes.Although various embodiments are specifically illustrated and describedherein, it will be appreciated that modifications and variations of theinvention are covered by the above teachings and are within the purviewof the appended claims without departing from the spirit and intendedscope of the invention. For example, certain aspect ratios arediscussed, however, the present invention is applicable to other aspectratios. Furthermore, this example should not be interpreted to limit themodifications and variations of the invention covered by the claims butis merely illustrative of possible variations.

1. A method (100) for controlling an image being displayed on a displayfrom a set-top box comprising: a) tuning (101) to a user selectedchannel; b) determining (102) if the user selected channel includesprogramming having a first aspect ratio; c) employing (104) a firstoutput format, if the user selected channel does not include programminghaving the first aspect ratio; d) continuing with steps e) through l),if the user selected channel contains programming having the firstaspect ratio: e) checking (103) an override setting for the first aspectratio; f) if the override setting for the first aspect ratio is not setto a stretch setting, applying (105) a predetermined procedure for afirst aspect ratio override feature; g) if the override setting for thefirst aspect ratio is set to a stretch setting then continuing withsteps h) through l); h) stretching (106) video from the user selectedchannel having the first aspect ratio to fill a frame having a secondaspect ratio that is different than the first aspect ratio using apredetermined stretching function; i) maintaining (107) any overlayinggraphics with their original aspect ratio; k) converting (108) aresulting video to an output format specified by the first output formatsetting, wherein: (i) if the first output format setting comprises 1080i(109), the stretched video comprises 1080i (112); (ii) if the firstoutput setting comprises 720p (110), the stretched video comprises 720p(113); and (iii) if the first output setting comprises 480p (111), thestretched video comprises 480p (114); and l) output (115) the stretchedand converted video frames on one or more component video outputs,whereby only a plurality of primary high definition video outputsdisplay stretched video frame and a plurality of secondary standarddigital video outputs display 4:3 video.
 2. A method (100) forcontrolling an image being output from a set-top box comprising:determining (102) if a user selected channel contains programming havinga first aspect ratio; and stretching (106) automatically video from theuser selected channel having the first aspect ratio, if the userselected channel contains programming having the first aspect ratio, tofill a frame having a second aspect ratio that is different than thefirst aspect ratio using a predetermined stretching function.
 3. Themethod (100) according to claim 2, further comprising initiating saiddetermining and said stretching upon tuning (101) to a user selectedchannel.
 4. The method (100) according to claim 2, further comprising:employing (104) a first output format if the user selected channel doesnot contain programming having the first aspect ratio.
 5. The method(100) according to claim 2, further comprising: determining (103),before said stretching, if an override setting exists for the firstaspect ratio, and if the override setting for the first aspect ratio isnot set to a stretch setting then applying (105)a predeterminedprocedure for a first aspect ratio override feature rather than saidstretching, and if the override setting for the first aspect ratio isset to the stretch setting then performing said stretching (106).
 6. Themethod (100) according to claim 2, further comprising: maintaining (107)any overlaying graphics with their original aspect ratio.
 7. The method(100) according to claim 6, wherein said overlaying graphics includes anelectronic programming guide and closed-captioning text.
 8. The method(100) according to claim 2, further comprising: converting (108) aresulting video to an output format specified by the first output formatsetting.
 9. The method (100) according to claim 8, wherein: (i) if thefirst output format setting comprises 1080i (109), the stretched videocomprises 1080i (112); (ii) if the first output setting comprises 720p(110), the stretched video comprises 720p (113); and (iii) if the firstoutput setting comprises 480p (111), the stretched video comprises 480p(114).
 10. The method (100) according to claim 2, further comprising:outputting (115) a plurality of stretched and converted video frames onone or more component video outputs.
 11. The method (100) according toclaim 2, wherein only a plurality of primary high definition videooutputs display stretched video frames and a plurality of secondarystandard digital video outputs display video having the first aspectratio.
 12. The method (100) according to claim 11, wherein the pluralityof primary high definition video outputs include YPrPb outputs.
 13. Themethod (100) according to claim 11, wherein the plurality of secondarystandard digital video outputs include one or more selected from thegroup of: a composite video output, an S-Video output and an RF videooutput.
 14. A method (200) for controlling video output from a set-topbox comprising: receiving (201) a zoom toggle command from a user via aremote control unit; determining (202) if a user-selected programincludes a second aspect ratio different than a first aspect ratio;determining (203) a television type setting from a user settings screen;selecting (206) a next available zoom mode for a second aspect ratiotelevision type if the television type setting is set for the secondaspect ratio and setting (207) an output format to a mode specified by afirst predetermined output setting; selecting (208) a next availablezoom mode for a first aspect ratio television type if the televisiontype setting is set for the first aspect ratio, and determining (209) ifa zoom mode selected is a predetermined mode and, if so, setting (211)an output format to an override mode for the first aspect ratio,otherwise setting (210) an output format to a mode specified by thefirst predetermined output setting; and ignoring (205) the zoom togglecommand if the television type setting is not set for the first aspectratio or the second aspect ratio.
 15. A method (200) for controllingvideo output from a set-top box upon receiving a zoom toggle commandfrom a user via a remote control unit, said method comprising:determining (202) if a user-selected program includes a second aspectratio different than a first aspect ratio and ignoring (205) the zoomtoggle command if the programming does not include the second aspectratio; selecting (206; 208) a next available zoom mode for a first orsecond aspect ratio television type if the television type setting isset for the first or second aspect ratio, respectively, and setting(207; 210) an output format to a mode specified by a first predeterminedoutput setting.
 16. The method (200) according to claim 15, furthercomprising: determining (203) a television type setting from a usersettings screen.
 17. The method according to claim 15, furthercomprising: ignoring (205) the zoom toggle command if the televisiontype setting is not set for the first aspect ratio or the second aspectratio.
 18. The method (200) according to claim 15, further comprising:determining (209) if a zoom mode selected for the first aspect ratiotelevision type is a predetermined mode and, if so, setting (211) anoutput format to an override mode for the first aspect ratio.
 19. Anapparatus (220) for controlling a video image output from a set-top boxcomprising: a processor (221); a memory (222) being coupled to theprocessor and having encoded therein computer readable instructionscausing the processor (221_ to control an image being output to adisplay (225) by: determining (102) if a user selected channel containsprogramming having a first aspect ratio; and stretching (106)automatically video from the user selected channel having the firstaspect ratio, if the user selected channel contains programming havingthe first aspect ratio, to fill a frame having a second aspect ratiothat is different than the first aspect ratio using a predeterminedstretching function.
 20. The apparatus (220) according to claim 19,further comprising a remote control unit coupled to the processor (226),wherein said processor (221) initiates said determining and saidstretching upon receiving a command to tune to a user selected channelfrom the remote control unit (226).
 21. The apparatus (220) according toclaim 19, wherein said processor (221) employs a first output format ifthe user selected channel does not contain programming having the firstaspect ratio.
 22. The apparatus (220) according to claim 19, whereinsaid processor (221) determines (103), before said stretching, if anoverride setting exists for the first aspect ratio, and if the overridesetting for the first aspect ratio is not set to a stretch setting thenapplies (105) a predetermined procedure for a first aspect ratiooverride feature rather than said stretching (106), and if the overridesetting for the first aspect ratio is set to the stretch setting thenperforms said stretching (106).
 23. The apparatus (220) according toclaim 19, wherein said processor (221) maintains any overlaying graphicswith their original aspect ratio.
 24. The apparatus (220) according toclaim 19, wherein said processor (221) converts a resulting video to anoutput format specified by the first output format setting.
 25. Theapparatus (220) according to claim 19, wherein said processor outputs aplurality of stretched and converted video frames on one or morecomponent video outputs.
 26. The apparatus (220) according to claim 19,further comprising a plurality of primary high definition video outputswhich include stretched video frames and a plurality of secondarystandard digital video outputs which include video having the firstaspect ratio.
 27. An apparatus (230) for controlling video comprising: aremote control unit (226); a receiver (223) to interact with the remotecontrol unit (226) and to receive a zoom toggle command from a user viasaid remote control unit (226); a processor (221) determining if auser-selected program includes a second aspect ratio different than afirst aspect ratio and ignoring the zoom toggle command if theprogramming does not include the second aspect ratio; and a graphicaluser interface (224) via which a user can enter a television typesetting via a user settings screen, wherein said processor (221)determines the television type setting from the user settings screen,and selects a next available zoom mode for a first or second aspectratio television type if the television type setting is set for thefirst or second aspect ratio, respectively, and sets an output format toa mode specified by a first predetermined output setting.
 28. Theapparatus (230) according to claim 27, wherein said processor (221)ignores the zoom toggle command if the television type setting is notset for the first aspect ratio or the second aspect ratio.
 29. Theapparatus (230) according to claim 27, wherein said processor (221)determines if a zoom mode selected for the first aspect ratio televisiontype is a predetermined mode and, if so, sets an output format to anoverride mode for the first aspect ratio.
 30. A method (200) forcontrolling a display of video having a 16:9 aspect ratio image using aset-top box, comprising: cycling (206) among a plurality of selectablezoom modes upon receiving a zoom toggle command from a remote control;and moving (206) to a top of a list of the plurality of selectable zoommodes upon reaching a bottom of the list of the plurality of selectablezoom modes, wherein the plurality of selectable zoom modes includes: (1)a “No Zoom” mode to remove all ASTB Zoom Mode processing to view videobroadcast “as is”; (2) a zoom mode that takes a centered 14:9 cutout ofa 16:9 broadcast image and horizontally stretches the 16:9 broadcastimage to fill a 16:9 frame of a display; (3) a zoom mode that takes acentered 4:3 cutout of a 16:9 broadcast image and horizontally stretchesthe 16:9 broadcast image to fill a 16:9 frame of a display; and (4) azoom mode that takes a centered 4:3 cutout of a 16:9 broadcast image andhorizontally and vertically stretches the 16:9 broadcast image to fill a16:9 frame of a display; and (5) a zoom mode that takes a centered 4:3cutout of the 16:9 broadcast and converts the output format of the ASTBto a known 4:3 format (either 480i or 480p).
 31. A method (24) forcontrolling an image being output from a set-top receiver to a displaycomprising: receiving (241) information as to an aspect ratio of thedisplay to which the set-top receiver is connected; manipulating (242) areceived video image in the set-top receiver using a stretch/zoomtechnique to provide at least one customized zoom mode guaranteed tofill an entire screen of the display and to provide one or moreadditional zoom modes that are independent of the aspect ratio of thedisplay; outputting (243) the manipulated video image using one or moreATSC formats; receiving (244) input from a viewer to select one of theat least one customized zoom mode or the one or more additional zoommodes, or setting the zoom mode automatically based on the aspect ratioof the display without requiring additional input from the user.